Because it would be the equivalent of a natural built-in evil bit and an extremely bizarre thing - for the same reason that the evil bit is unlikely to be used.
Any system that claims to work on that sort of input is almost certainly picking up socio-economic status of different races, or something similar, with no causal predictive power.
Any system that claims to work on that sort of input is almost certainly picking up socio-economic status of different races, or something similar, with no causal predictive power.